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Message-ID: <20210513110045.5yrootk4bv6u6lya@earth.universe>
Date: Thu, 13 May 2021 13:00:45 +0200
From: Sebastian Reichel <sebastian.reichel@...labora.com>
To: Ikjoon Jang <ikjn@...omium.org>
Cc: linux-pm@...r.kernel.org, Hsinyi Wang <hsinyi@...omium.org>,
linux-kernel@...r.kernel.org
Subject: Re: [RESEND PATCH v2] power: supply: sbs-battery: cache constant
string properties
Hi,
On Thu, May 13, 2021 at 10:03:08AM +0800, Ikjoon Jang wrote:
> Currently sbs-battery supports three string properties -
> manufacturer, model_name, and chemistry. Buffers for those
> properties are currently defined as global variables.
>
> This patch moves those global variables into struct sbs_info
> and cache/reuse them as they are all constant values.
Thanks, that's a nice cleanup. I have a two comments, though.
Please find them inline.
> Signed-off-by: Ikjoon Jang <ikjn@...omium.org>
> Tested-by: Hsin-Yi Wang <hsinyi@...omium.org>
>
> ---
> Resend v2: Adds Tested-by, escape from v1 mail thread.
>
> Changes in v2:
> - change function name of sbs_get_battery_string_property()
> to sbs_get_constant_string()
> - use cached string properties
> - use cached technology value in sbs_get_chemistry()
>
> drivers/power/supply/sbs-battery.c | 140 +++++++++++++++++------------
> 1 file changed, 82 insertions(+), 58 deletions(-)
>
> diff --git a/drivers/power/supply/sbs-battery.c b/drivers/power/supply/sbs-battery.c
> index 4bf92831cb06..414de9bc47bf 100644
> --- a/drivers/power/supply/sbs-battery.c
> +++ b/drivers/power/supply/sbs-battery.c
> @@ -188,6 +188,14 @@ static const enum power_supply_property sbs_properties[] = {
> /* Supports special manufacturer commands from TI BQ20Z65 and BQ20Z75 IC. */
> #define SBS_FLAGS_TI_BQ20ZX5 BIT(0)
>
> +static const enum power_supply_property string_properties[] = {
> + POWER_SUPPLY_PROP_TECHNOLOGY,
> + POWER_SUPPLY_PROP_MANUFACTURER,
> + POWER_SUPPLY_PROP_MODEL_NAME,
> +};
> +
> +#define NR_STRING_BUFFERS ARRAY_SIZE(string_properties)
> +
> struct sbs_info {
> struct i2c_client *client;
> struct power_supply *power_supply;
> @@ -201,11 +209,22 @@ struct sbs_info {
> struct delayed_work work;
> struct mutex mode_lock;
> u32 flags;
> + int technology;
> + char strings[NR_STRING_BUFFERS][I2C_SMBUS_BLOCK_MAX + 1];
> };
>
> -static char model_name[I2C_SMBUS_BLOCK_MAX + 1];
> -static char manufacturer[I2C_SMBUS_BLOCK_MAX + 1];
> -static char chemistry[I2C_SMBUS_BLOCK_MAX + 1];
> +static char *sbs_get_string_buf(struct sbs_info *chip,
> + enum power_supply_property psp)
> +{
> + int i = 0;
> +
> + for (i = 0; i < NR_STRING_BUFFERS; i++)
> + if (string_properties[i] == psp)
> + return chip->strings[i];
> +
> + return ERR_PTR(-EINVAL);
> +}
> +
> static bool force_load;
>
> static int sbs_read_word_data(struct i2c_client *client, u8 address);
> @@ -639,17 +658,45 @@ static int sbs_get_battery_property(struct i2c_client *client,
> return 0;
> }
>
> -static int sbs_get_battery_string_property(struct i2c_client *client,
> - int reg_offset, enum power_supply_property psp, char *val)
> +static int sbs_get_property_index(struct i2c_client *client,
> + enum power_supply_property psp)
> {
> - s32 ret;
> + int count;
> +
> + for (count = 0; count < ARRAY_SIZE(sbs_data); count++)
> + if (psp == sbs_data[count].psp)
> + return count;
>
> - ret = sbs_read_string_data(client, sbs_data[reg_offset].addr, val);
> + dev_warn(&client->dev,
> + "%s: Invalid Property - %d\n", __func__, psp);
>
> - if (ret < 0)
> - return ret;
> + return -EINVAL;
> +}
>
> - return 0;
> +static const char *sbs_get_constant_string(struct sbs_info *chip,
> + enum power_supply_property psp)
> +{
> + int ret;
> + char *buf;
> + u8 addr;
> +
> + buf = sbs_get_string_buf(chip, psp);
> + if (IS_ERR(buf))
> + return buf;
> +
> + if (!buf[0]) {
> + ret = sbs_get_property_index(chip->client, psp);
> + if (ret < 0)
> + return ERR_PTR(ret);
> +
> + addr = sbs_data[ret].addr;
> +
> + ret = sbs_read_string_data(chip->client, addr, buf);
> + if (ret < 0)
> + return ERR_PTR(ret);
> + }
> +
> + return buf;
> }
>
> static void sbs_unit_adjustment(struct i2c_client *client,
> @@ -772,48 +819,34 @@ static int sbs_get_battery_serial_number(struct i2c_client *client,
> return 0;
> }
>
> -static int sbs_get_property_index(struct i2c_client *client,
> - enum power_supply_property psp)
> -{
> - int count;
> - for (count = 0; count < ARRAY_SIZE(sbs_data); count++)
> - if (psp == sbs_data[count].psp)
> - return count;
> -
> - dev_warn(&client->dev,
> - "%s: Invalid Property - %d\n", __func__, psp);
> -
> - return -EINVAL;
> -}
> -
> -static int sbs_get_chemistry(struct i2c_client *client,
> +static int sbs_get_chemistry(struct sbs_info *chip,
> union power_supply_propval *val)
> {
> - enum power_supply_property psp = POWER_SUPPLY_PROP_TECHNOLOGY;
> - int ret;
> + const char *chemistry;
>
> - ret = sbs_get_property_index(client, psp);
> - if (ret < 0)
> - return ret;
> + if (chip->technology >= POWER_SUPPLY_TECHNOLOGY_UNKNOWN)
> + return chip->technology;
This obviously must look like this:
val->intval = chip->technology;
return 0;
With your code you should only see correct technology for the
first read of the technology property. How did you test your
changes?
> - ret = sbs_get_battery_string_property(client, ret, psp,
> - chemistry);
> - if (ret < 0)
> - return ret;
> + chemistry = sbs_get_constant_string(chip, POWER_SUPPLY_PROP_TECHNOLOGY);
> +
> + if (IS_ERR(chemistry))
> + return PTR_ERR(chemistry);
>
> if (!strncasecmp(chemistry, "LION", 4))
> - val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
> + chip->technology = POWER_SUPPLY_TECHNOLOGY_LION;
> else if (!strncasecmp(chemistry, "LiP", 3))
> - val->intval = POWER_SUPPLY_TECHNOLOGY_LIPO;
> + chip->technology = POWER_SUPPLY_TECHNOLOGY_LIPO;
> else if (!strncasecmp(chemistry, "NiCd", 4))
> - val->intval = POWER_SUPPLY_TECHNOLOGY_NiCd;
> + chip->technology = POWER_SUPPLY_TECHNOLOGY_NiCd;
> else if (!strncasecmp(chemistry, "NiMH", 4))
> - val->intval = POWER_SUPPLY_TECHNOLOGY_NiMH;
> + chip->technology = POWER_SUPPLY_TECHNOLOGY_NiMH;
> else
> - val->intval = POWER_SUPPLY_TECHNOLOGY_UNKNOWN;
> + chip->technology = POWER_SUPPLY_TECHNOLOGY_UNKNOWN;
>
> - if (val->intval == POWER_SUPPLY_TECHNOLOGY_UNKNOWN)
> - dev_warn(&client->dev, "Unknown chemistry: %s\n", chemistry);
> + if (chip->technology == POWER_SUPPLY_TECHNOLOGY_UNKNOWN)
> + dev_warn(&chip->client->dev, "Unknown chemistry: %s\n", chemistry);
> +
> + val->intval = chip->technology;
>
> return 0;
> }
> @@ -857,6 +890,7 @@ static int sbs_get_property(struct power_supply *psy,
> int ret = 0;
> struct sbs_info *chip = power_supply_get_drvdata(psy);
> struct i2c_client *client = chip->client;
> + const char *str;
>
> if (chip->gpio_detect) {
> ret = gpiod_get_value_cansleep(chip->gpio_detect);
> @@ -882,7 +916,7 @@ static int sbs_get_property(struct power_supply *psy,
> break;
>
> case POWER_SUPPLY_PROP_TECHNOLOGY:
> - ret = sbs_get_chemistry(client, val);
> + ret = sbs_get_chemistry(chip, val);
> if (ret < 0)
> break;
>
> @@ -934,23 +968,12 @@ static int sbs_get_property(struct power_supply *psy,
> break;
>
> case POWER_SUPPLY_PROP_MODEL_NAME:
> - ret = sbs_get_property_index(client, psp);
> - if (ret < 0)
> - break;
> -
> - ret = sbs_get_battery_string_property(client, ret, psp,
> - model_name);
> - val->strval = model_name;
> - break;
> -
> case POWER_SUPPLY_PROP_MANUFACTURER:
> - ret = sbs_get_property_index(client, psp);
> - if (ret < 0)
> - break;
> -
> - ret = sbs_get_battery_string_property(client, ret, psp,
> - manufacturer);
> - val->strval = manufacturer;
> + str = sbs_get_constant_string(chip, psp);
> + if (IS_ERR(str))
> + ret = PTR_ERR(str);
> + else
> + val->strval = str;
> break;
>
> case POWER_SUPPLY_PROP_MANUFACTURE_YEAR:
> @@ -1097,6 +1120,7 @@ static int sbs_probe(struct i2c_client *client)
> psy_cfg.of_node = client->dev.of_node;
> psy_cfg.drv_data = chip;
> chip->last_state = POWER_SUPPLY_STATUS_UNKNOWN;
> + chip->technology = -1;
> mutex_init(&chip->mode_lock);
>
> /* use pdata if available, fall back to DT properties,
You need to invalidate the cached values when battery is unplugged,
since a different battery may be attached afterwards.
-- Sebastian
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